Substrate developing method, substrate processing method and developing solution supply nozzle

ABSTRACT

According to the present invention, an anti-reflective film formed under a resist film is removed in a photolithography process of a wafer without affecting the resist film. According to the present invention, in a photolithography process of a substrate, an anti-reflective film having solubility in the developing solution is formed and thereafter a resist film is formed. In development treatment after exposure processing, a developing solution is supplied to the substrate to develop the resist film. At an instant when the development of the resist film is finished, a second developing solution lower in concentration than the developing solution is supplied to the substrate. Only the anti-reflective film is dissolved and removed by the supply of the second developing solution.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a Continuation application of application Ser. No. 12/068,897,filed on Feb. 13, 2008, which is a Divisional application of applicationSer. No. 11/010,347, filed on Dec. 14, 2004, now U.S. Pat. No.7,367,710, claiming Japanese Priority No. 2003-421329, filed Dec. 18,2003, the entirety of which is incorporated herein by reference for allpurposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate developing method, asubstrate processing method, and a developing solution supply nozzle.

2. Description of the Related Art

In a photolithography process in fabrication processes of asemiconductor device, resist coating treatment in which a resist film isformed by applying a resist solution on a film to be etched that isformed on a surface of, for example, a wafer, exposure processing inwhich the resist film on the wafer is exposed in a predeterminedpattern, development treatment in which the resist film is developed bysupplying a developing solution to the exposed wafer, and etchingtreatment in which the film to be etched is etched, using the resistfilm in the predetermined pattern as a mask, and so on are performed insequence.

In the photolithography process, an anti-reflective film is sometimesformed as a base film of the resist film prior to the resist coatingtreatment in order to, for example, prevent the resist film from beingexcessively exposed by light which is reflected on the film to be etchedafter transmitting through the resist film during the exposureprocessing.

When, for example, the base film is thus formed between the film to beetched and the resist film, it is necessary to separately etch the basefilm on an upper layer of the film to be etched before the film to beetched is etched. The etching treatment of this base film has beengenerally conducted in such a manner that an etching gas is plasmatizedin a chamber housing a wafer to cause a chemical reaction of a surfaceof the base film with plasma particles (Japanese Patent ApplicationLaid-open No. Hei 8-97191).

However, due to the use of high-energy plasma particles in the etchingtreatment of the base film, the resist film is greatly damaged, and forexample, as shown in FIG. 14, a surface of a resist film R on an upperlayer is etched off to sometimes cause great inclination of a side faceof the resist film R which should be in a rectangular shape.

With such inclination of the side face of the resist film R, in theetching treatment of the film to be etched, the film to be etched isetched more than necessary to become smaller than a predetermined size,so that a pattern with a desired line width and dimension is not formedon the wafer. Especially in recent years when high density andmicrofabrication of semiconductor devices are progressing, realizing aphotolithography process with high dimensional precision has become animportant issue.

Further, in the conventional etching treatment of the base film, a largeamount of an upper surface of the resist film R is also sometimes etchedoff in a vertical direction. This reduces the total film thickness ofthe resist film R and the base film, which sometimes disables the resistfilm R from fully functioning as a mask for the film to be etched.

SUMMARY OF THE INVENTION

The present invention was made in view of the above-described respects,and it is an object of the present invention to provide a substratedeveloping method and a substrate processing method capable of removinga base film formed on a lower layer of a resist film without affectingthe resist film in a photolithography process of a substrate such as awafer, and to provide a developing solution supply nozzle used in theseprocessing methods.

According to a first aspect of the present invention, the presentinvention is a method of developing a substrate having a predeterminedbase film formed on a lower layer of a resist film, the methodcomprising the steps of: supplying a developing solution to thesubstrate to develop the resist film formed on the substrate; andthereafter supplying a predetermined treatment solution to the substrateto dissolve the base film at a portion exposed by the development of theresist film.

According to this invention, unlike in the prior art, the base film isdissolved by the treatment solution instead of being etched byhigh-energy plasma particles. Therefore, the resist film on the upperlayer is not damaged greatly and it can be prevented that a surface ofthe resist film is etched off while the base film is removed. As aresult, when a film to be etched on a lower layer is etched, following,for example, the removal of the base film, the resist film functions asa mask with accurate size. Consequently, a pattern with high dimensionalaccuracy can be formed on the substrate. In addition, since the etchingof the base film, which has been conventionally necessary, is notrequired, the time required for forming the pattern can be shortened,resulting in an improved throughput of the substrate processing.

The base film may have solubility in the developing solution, and thepredetermined treatment solution may be a developing solution lower inproperty of dissolving the resist film than the aforesaid developingsolution. In such a case, it is possible to dissolve the base film bythe developing solution lower in dissolving property than the developingsolution used for developing the resist film, thereby removing the basefilm after the resist film is developed by the developing solution. Thisprevents the degeneration of the resist film since the developingsolution is used as the treatment solution for dissolving the base film.Further, the use of the developing solution lower in property ofdissolving the resist film prevents excessive-development of the resistfilm.

Incidentally, if density of dissolved portions is nonuniform in theresist film when it is developed, the developing solution in denseportions is lower in developing capability than the developing solutionin scarce portions after dissolving the resist film. Therefore, if, forexample, the developing solution used for developing the resist film isused as it is to dissolve the base film, it would cause difference insolubility of the base film among the scarce portions and the denseportions of the resist film. According to the present invention, sincethe fresh developing solution appropriate for dissolving the base filmis supplied after the development of the resist film is finished, thedissolution of the base film can be uniform on the surface of thesubstrate irrespective of density variation of the dissolved portions ofthe resist film. Note that the predetermined treatment solution may be adeveloping solution lower in at least one of concentration andtemperature than the developing solution used for developing the resistfilm.

The predetermined treatment solution may be supplied to the substrate tostart dissolving the base film when the dissolution of the resist filmreaches a surface of the base film in accordance with progress of thedevelopment of the resist film by the developing solution. This enablesappropriate shift from the development of the resist film to thedissolution of the base film.

The developing method may further comprise the step of removing thedeveloping solution on the substrate between the step of developing theresist film on the substrate and the step of supplying the predeterminedtreatment solution to the substrate. In this case, it is possible toonce stop the development of the resist film completely and tothereafter start the removal of the base film anew, which enables morereliable prevention of excessive development of the resist film.

The supply of the predetermined treatment solution to the substrate maybe performed by using a nozzle having discharge ports that are arrangedin an area longer than a specific direction dimension of the substrateand by moving the nozzle discharging the predetermined treatmentsolution above the substrate. Further, the same nozzle for supplying thepredetermined treatment solution may be used when the developingsolution is supplied for developing the resist film. Note that the basefilm in the inventions described hitherto may be an anti-reflective filmpreventing reflection of light in exposure processing.

According to another aspect of the present invention, the presentinvention is a substrate processing method including a photolithographyprocess, and the photolithography process includes the steps of: formingon a substrate an anti-reflective film having solubility in a developingsolution used in development treatment and preventing reflection oflight in exposure processing, before forming a resist film on thesubstrate; and in the development treatment after the exposureprocessing, supplying to the substrate a developing solution that islower in at least one of concentration and temperature than thedeveloping solution used in the development treatment of the resistfilm, to thereby dissolve a portion of the anti-reflective film exposedby the development of the resist film, before supplying the developingsolution to the substrate to develop the resist film.

According to still another aspect of the present invention, the presentinvention is a developing solution supply nozzle supplying a developingsolution to a substrate, the nozzle comprising: a main body in a slendershape having a length substantially equal to or larger than a specificdirection dimension of the substrate; a developing solution storagechamber extending in the main body in a longitudinal direction of themain body to store the developing solution; a liquid storage chamberextending in the main body in the longitudinal direction of the mainbody to store a predetermined liquid that is to be mixed in thedeveloping solution; and a mixing chamber which extends in the main bodyin the longitudinal direction of the main body to communicate with thedeveloping solution storage chamber and the liquid storage chamber andin which the developing solution flowing from the developing solutionstorage chamber and the liquid flowing from the liquid storage chamberare mixed. The nozzle further includes: discharge ports provided in alower surface of the main body to communicate with the mixing chamber,and having openings arranged along the longitudinal direction todischarge the developing solution mixed in the mixing chamber; and astirring stick extending in the mixing chamber along the longitudinaldirection to stir the developing solution and the liquid which flow intothe mixing chamber. The developing solution supply nozzle of thisinvention further includes a rotation driving section driving thestirring stick to rotate around an axis of the stirring stick.

According to the developing solution supply nozzle as structured above,it is possible to mix the developing solution supplied from thedeveloping solution storage chamber and the liquid supplied from theliquid storage chamber at a predetermined ratio in the mixing chamber toproduce a developing solution, for example, with a predeterminedconcentration or at a predetermined temperature. In the mixing chamber,the rotation driving section can actively rotate the stirring stick, sothat it is possible to fully stir the developing solution and the liquidflowing thereto to produce the developing solution with uniformconcentration or at uniform temperature. According to this developingsolution supply nozzle, changing the mixing ratio of the developingsolution and the liquid in the mixing chamber will enable the productionof a plurality of kinds of developing solutions different inconcentration or temperature. Further, this developing solution supplynozzle can be used, for instance, for supplying the developing solutionto a substrate to develop a resist film and for thereafter supplying adeveloping solution lower in concentration or temperature to dissolve abase film such as an anti-reflective film. Therefore, the substratedeveloping method and the substrate processing method according to theaforesaid inventions can be suitably carried out.

In a developing solution supply nozzle according to yet another aspectof the present invention, instead of rotating the stirring stickextending along the longitudinal direction, a flow path extending fromthe developing solution storage chamber to communicate with the mixingchamber and a flow path extending from the liquid storage chamber tocommunicate with the mixing chamber are formed so that the developingsolution and the liquid flowing into the mixing chamber from thedeveloping solution storage chamber and the liquid storage chamber flowin directions deviated from an axial center of the stirring stick in themixing chamber to collide with the stirring stick.

According to this invention, it is possible to mix in the mixing chamberthe developing solution supplied from the developing solution storagechamber and the predetermined liquid supplied from the liquid storagechamber at a predetermined ratio to produce the developing solution, forexample, with a predetermined concentration or at a predeterminedtemperature. In the mixing chamber, the developing solution suppliedfrom the developing solution storage chamber and the liquid suppliedfrom the liquid storage chamber flow in the directions deviated from theaxial center of the stirring stick to collide with the stirring stick,so that the stirring stick is rotated by this collision. The developingsolution and the liquid flowing into the mixing chamber can be fullystirred by the rotation of the stirring stick, so that a developingsolution uniform in concentration or temperature can be produced in themixing chamber. According to this developing solution supply nozzle,changing a mixing ratio of the developing solution and the liquid in themixing chamber makes it possible to produce a plurality of kinds ofdeveloping solutions different in concentration or temperature.Therefore, it is possible, for example, to supply the developingsolution to a substrate to develop a resist film, and thereafter supplya developing solution lower in concentration or temperature to thesubstrate to dissolve a base film such as an anti-reflective film,through the use of the developing solution supply nozzle. Therefore, thesubstrate developing method and the substrate processing methodaccording to the aforesaid inventions can be suitably carried out.

The stirring stick may be formed in a spiral shape and may be made of aporous material. This can further promote the mixture of the developingsolution and the liquid in the mixing chamber.

The mixing chamber may have a circular vertical cross section as viewedin a direction along an axis of the stirring stick. This structurefurther promotes the rotation of the stirring stick around the axisthereof by the fluids flowing, for example, along an inner wall of themixing chamber, so that the developing solution and the liquid arefurther stirred fully.

A flow path of the developing solution from the mixing chamber to eachof the discharge ports in the main body may be formed to once narrowdown on a downstream side of the mixing chamber and thereafter widen.This structure increases the residence time of the liquid in the mixingchamber since the vicinity of an outlet of the mixing chamber narrowsdown, thereby promoting the mixture of the developing solution and theliquid. Further, since the flow path widens toward the outlet of thedischarge port, the pressure of the developing solution which has risenat the outlet of the mixing chamber can be reduced. This as a resultreduces shock of the collision of the developing solution with thesurface of the substrate, so that a development flaw caused by thecollision of the developing solution can be prevented.

The predetermined liquid may be pure water or may be a developingsolution lower in temperature than the developing solution stored in thedeveloping solution storage chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view schematically showing the configuration of acoating and developing system in an embodiment of the present invention;

FIG. 2 is a front view of the coating and developing system in FIG. 1;

FIG. 3 is a rear view of the coating and developing system in FIG. 1;

FIG. 4 is an explanatory view of a vertical cross section schematicallyshowing the configuration of a developing unit;

FIG. 5 is an explanatory view of a horizontal cross sectionschematically showing the configuration of the developing unit;

FIG. 6 is a vertical cross-sectional view of a developing solutionsupply nozzle viewed in an X-direction;

FIG. 7 is a vertical cross-sectional view of the developing solutionsupply nozzle viewed in a Y direction;

FIG. 8 is an explanatory view to show how a wafer changes as processingof the wafer progresses;

FIG. 9 is an explanatory view to show how the wafer changes as theprocessing of the wafer progresses;

FIG. 10 is a perspective view of a stirring stick in which a groove isformed;

FIG. 11 is a vertical cross-sectional view of a developing solutionsupply nozzle viewed in the X direction, the nozzle including a porousstirring stick;

FIG. 12 is a vertical cross-sectional view of a developing solutionsupply nozzle viewed in the X-direction, the nozzle including graduallywidening discharge ports;

FIG. 13 is a vertical cross-sectional view of a developing solutionsupply nozzle viewed in the X-direction, in which directions of a firstand a second communicating path are changed; and

FIG. 14 is an explanatory view showing the state of a resist film whenan anti-reflective film is etched by a conventional method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, a preferred embodiment of the present invention will bedescribed. FIG. 1 is a plane view schematically showing theconfiguration of a coating and developing system 1 in which aphotolithography process of substrate processing is carried out, FIG. 2is a front view of the coating and developing system 1, and FIG. 3 is arear view of the coating and developing system 1.

As shown in FIG. 1, the coating and developing system 1 includes acassette station 2, a processing station 3, and an interface section 4which are integrally connected. In the cassette station 2, for example,25 pieces of wafers W per cassette are carried in a unit into/out of thecoating and developing system 1 from/into the outside and the wafer W iscarried into/out of a cassette C. In the processing station 3, variouskinds of processing units for performing predetermined processing onwafer-by-wafer basis in coating and development treatment are arrangedin multiple tiers. In the interface section 4, the wafer W is deliveredto/from a not-shown aligner provided adjacent to the processing station3. In the cassette station 2, a plurality of cassettes C are mountablein a line in an X direction (up/down direction in FIG. 1) atpredetermined positions of a cassette mounting table 5 which serves as amounting section. The cassette station 2 has a wafer carrier 7 movablein the X direction on a carrier guide 6. The wafer carrier 7 is alsomovable in a wafer alignment direction (Z direction; vertical direction)of the wafers W housed in the cassette C and is capable of selectivelyaccessing the wafer W in each of the cassettes C arranged in the Xdirection.

The wafer carrier 7 is rotatable in a θ direction around a Z axis and isalso capable of accessing a temperature controller 50 and a transitiondevice 51 belonging to a later-described third processing unit group G3on a processing station 3 side.

The processing station 3 adjacent to the cassette station 2 includes,for example, five processing unit groups G1 to G5 in each of which aplurality of processing units are arranged in multiple tiers. On anX-direction negative side (lower side in FIG. 1) in the processingstation 3, the first processing unit group G1 and the second processingunit group G2 are arranged in this order from the cassette station 2side. On an X-direction positive side (upper side in FIG. 1) in theprocessing station 3, the third processing unit group G3, the fourthprocessing unit group G4, and the fifth processing unit group G5 arearranged in this order from the cassette station 2 side. A first carrier10 is provided between the third processing unit group G3 and the fourthprocessing unit group G4. The first carrier 10 is capable of selectivelyaccessing the first processing unit group G1, the third processing unitgroup G3, and the fourth processing unit group G4 to transfer the waferW thereto/therefrom. A second carrier 11 is provided between the fourthprocessing unit group G4 and the fifth processing unit group G5. Thesecond carrier 11 is capable of selectively accessing the secondprocessing unit group G2, the fourth processing unit group G4, and thefifth processing unit group G5 to transfer the wafer Wthereto/therefrom.

As shown in FIG. 2, in the first processing unit group G1, liquidtreatment units each supplying a predetermined liquid to the wafer W fortreatment, for example, resist coating units 20, 21, 22 each applying aresist solution to the wafer W and bottom coating units 23, 24 eachforming an anti-reflective film as a base film for preventing reflectionof light of exposure processing are stacked in five tiers in this orderfrom the bottom. In the second processing unit group G2, liquidtreatment units, for example, developing units 30 to 34 that performdevelopment treatment according to this embodiment are stacked in fivetiers in this order from the bottom. Further, on the lowest tiers of thefirst processing unit group G1 and the second processing unit group G2,chemical chambers 40, 41 for supplying various kinds of treatmentsolutions to the liquid treatment units in the processing unit groups G1and G2 are provided respectively.

For example, as shown in FIG. 3, in the third processing unit group G3,the temperature controller 50, the transition unit 51 where the deliveryof the wafer W is performed, high-precision temperature controllers 52to 54 heating the wafer W under precisely controlled temperature, andhigh-temperature thermal processing units 55 to 58 heating the wafer athigh temperature are stacked in nine tiers in this order from thebottom.

In the fourth processing unit group G4, for example, a high-precisiontemperature controller 60, pre-baking units 62 to 64 heating the wafer Wwhich has been subjected to resist coating treatment, and post-bakingunits 65 to 69 heating the wafer W which has been subjected to thedevelopment treatment are stacked in ten tiers in this order from thebottom.

In the fifth processing unit group G5, a plurality of thermal processingunits for thermally processing the wafer W, for example, high-precisiontemperature controllers 70 to 73 and post-exposure baking units 74 to 79thermally processing the wafer W which has been subjected to theexposure processing are stacked in ten tiers in this order from thebottom.

As shown in FIG. 1, a plurality of processing units are arranged on theX-direction positive side of the first carrier 10, and for example, asshown in FIG. 3, adhesion units 80, 81 for hydrophobic treatment of thewafer W and heating units 82, 83 for heating the wafer W are stacked infour tiers in this order from the bottom. As shown in FIG. 1, on theX-direction positive side of the second carrier 11, for example, an edgeexposure unit 84 for selectively exposing only an edge portion of thewafer W is disposed.

As shown in FIG. 1, the interface section 4 includes a first interfacepart 100 and a second interface part 101 arranged in this order from theprocessing station 3 side. In the first interface part 100, a wafercarrier 102 is disposed at a position corresponding to the fifthprocessing unit group G5. On X-direction sides of the wafer carrier 102,for example, buffer cassettes 103, 104 are installed. The wafer carrier102 is capable of accessing the processing units in the fifth processingunit group G5 and accessing the buffer cassettes 103, 104. In the secondinterface part 101, a wafer carrier 106 that moves on a carrier guide105 extending in the X direction is provided. The wafer carrier 106 ismovable in the Z direction and is also rotatable in the θ direction, sothat it is capable of accessing a not-shown aligner adjacent to thesecond interface part 101 and accessing the buffer cassette 104.Therefore, the wafer W in the processing station 3 can be carried to thealigner via the wafer carrier 102, the buffer cassettes 103, 104, andthe wafer carrier 106, and the wafer W after being subjected to theexposure processing can be carried into the processing station 3 via thewafer carrier 106, the buffer cassette 104, and the wafer carrier 102.

Next, the configuration of the aforesaid developing unit 30 will bedetailed. Since the developing units 31 to 34 have the sameconfiguration as that of the developing unit 30, they will not bedescribed. FIG. 4 is an explanatory view of a vertical cross sectionschematically showing the configuration of the developing unit 30, andFIG. 5 is an explanatory view of a horizontal cross section of thedeveloping unit 30.

As shown in FIG. 4, the developing unit 30 has a casing 30 a, and in acenter portion of the casing 30 a, a spin chuck 120 to hold the wafer Wis provided. The spin chuck 120 has a horizontal upper surface, and hasin this upper surface, for example, a suction port (not shown) to suckthe wafer W. By a sucking force from the sucking port, the wafer W canbe suction-held by the spin chuck 120.

The spin chuck 120 has, for example, a chuck driving mechanism 121 forrotating and moving up/down the spin chuck 120. The chuck drivingmechanism 121 includes: for example, a rotation driving section (notshown) such as a motor for rotating the spin chuck 120 around a verticalaxis at a predetermined speed; and a hoisting/lowering driving section(not shown) such as a motor or a cylinder for hoisting/lowering the spinchuck 120. The chuck driving mechanism 121 enables the wafer W on thespin chuck 60 to move up/down at a predetermined timing or to rotate ata predetermined speed.

Around the spin chuck 120, a cup 122 for receiving and collecting liquidscattering or dropping from the wafer W is provided. In the cup 122, forexample, an inner cup 123 surrounding the periphery of the spin chuck120, an outer cup 124 covering the outside of the inner cup 123, and abottom 125 covering lower surfaces of the inner cup 123 and the outercup 124 are separately formed. The inner cup 123 and the outer cup 124are capable of mainly receiving the liquid scattering to the outside ofthe wafer W, and the bottom 125 is capable of collecting the liquiddropping from inner walls of the inner cup 123 and the outer cup 124 andfrom the wafer W.

The inner cup 123 is formed, for example, in a substantially cylindricalshape and an upper end portion thereof inclines inner upward. The innercup 123 is capable of moving up/down when driven by thehoisting/lowering driving section 126 such as, for example, a cylinder.The outer cup 124 is formed in a substantially cylindrical shape whichis in a quadrangular shape in a plane view, for example, as shown inFIG. 5. The outer cup 124 is capable of moving up/down when driven by ahoisting/lowering driving section 127 such as, for example, a cylinderas shown in FIG. 4. The spin chuck 120 passes through the center portionof the bottom 125. Around the spin chuck 120, an annular member 128blocking the flow of, for example, the liquid entering a rear face froma front face of the wafer W is provided. The annular member 128 has apexportions adjacent to, for example, the rear face of the wafer W, and theapex portions can block the liquid flowing along the rear face of thewafer W. A drain pipe 129 communicating with, for example, a drainagesection of a factory is connected to the bottom 125, so that the liquidcollected in the cup 122 can be drained from the drain pipe 129 to theoutside of the developing unit 30.

As shown in FIG. 5, on the X-direction negative side (lower side in FIG.5) of the cup 122, a rail 140 extends along the Y direction. The rail140 is formed outside the cup 122, extending, for example, from theY-direction negative side (left side in FIG. 5) to the Y-directionpositive side (right side in FIG. 5). Two arms 141, 142 are attached tothe rail 140. The first arm 141 supports a developing solution supplynozzle 143. The first arm 141 is movable in the Y direction on the rail140 when driven by a driving mechanism 144, so that it is capable oftransferring the developing solution supply nozzle 143 from a standbysection 145 provided outside the cup 122 to the inside of the cup 122.Further, the first arm 141 is also movable in an up/down direction whendriven by, for example, the driving mechanism 144, so that it is capableof moving up/down the developing solution supply nozzle 143.

As shown in FIG. 4, the developing solution supply nozzle 143communicates with a developing solution supply source 151 installed, forexample, outside the casing 30 a via a developing solution supply pipe150. A developing solution with a predetermined concentration is storedin the developing solution source 151 in advance. The developingsolution supply source 151 has, for example, a temperature controlsection 152, so that the developing solution supply source 151 cansupply the developing solution at a predetermined temperature to thedeveloping solution supply nozzle 143. The developing solution supplynozzle 143 also communicates with a liquid supply source 154 storing,for example, a predetermined liquid via a liquid supply pipe 153. Inthis embodiment, the liquid supply source 154 stores pure water. Theliquid supply source 154 has, for example, a temperature control section155, so that the liquid supply source 154 can supply the pure water at apredetermined temperature to the developing solution supply nozzle 143.Valves 156, 157 capable of regulating the flow rate are attached to thedeveloping solution supply pipe 150 and the liquid supply pipe 153respectively, and the valves 156, 157 enable the supply of thedeveloping solution and the pure water at predetermined flow rates tothe developing supply nozzle 143.

Here, the structure of the developing solution supply nozzle 143 will bedetailed. As shown in FIG. 4 and FIG. 5, a main body 143 a of thedeveloping solution supply nozzle 143 is longer than, for example, adiameter dimension of the wafer W and has a slender shape along the Xdirection. As shown in FIG. 6, the main body 143 a has in an inner partthereof a developing solution storage chamber 160 and a liquid storagechamber 161 storing the developing solution and the pure waterrespectively which are introduced into the main body 143 a. Thedeveloping solution storage chamber 160 and the liquid storage chamber161 extend from one end portion to the other end portion of the mainbody 143 a along a longitudinal direction thereof as shown in FIG. 7. Asshown in FIG. 6, in an upper portion of the main body 143 a, adeveloping solution introducing path 162 extending from an upper surfacethereof to communicate with the developing solution storage chamber 160is formed. The developing solution introducing path 162 is connected tothe developing solution supply pipe 150. Further, in the upper portionof the main body 143 a, a liquid introducing path 163 extending from theupper surface thereof to communicate with the liquid storage chamber 161is formed. The liquid introducing path 163 is connected to the liquidsupply pipe 153. With such a structure, the developing solution suppliedinto the developing solution supply nozzle 143 through the developingsolution supply pipe 150 flows through the developing solutionintroducing path 162 to be stored in the developing solution storagechamber 160, and the pure water supplied through the liquid supply pipe153 flows through the liquid introducing path 163 to be stored in theliquid storage chamber 161.

Under the developing solution storage chamber 160 and the liquid storagechamber 161 in the main body 143 a, a mixing chamber 164 is formed. Themixing chamber 164 is formed along the longitudinal direction of themain body 143 a, extending from one end portion to the other end portionthereof, for example, as shown in FIG. 7. The mixing chamber 164, forexample, as shown in FIG. 6, has a substantially circular vertical crosssection as viewed in the X direction. As shown in FIG. 7, the mixingchamber 164 communicates with the developing solution storage chamber160 via a plurality of first communicating paths 165 arranged at equalintervals along the longitudinal direction. The mixing chamber 164 alsocommunicates with the liquid storage chamber 161 via a plurality ofsecond communicating paths 166 arranged at equal intervals along thelongitudinal direction. Therefore, the developing solution in thedeveloping storage chamber 160 and the pure water in the liquid storagechamber 161 flow through the respective communicating paths 165, 166 tobe mixed in the mixing chamber 164.

In the mixing chamber 164, a stirring stick 167 smaller in diameter thanthe mixing chamber 164 is provided as shown in FIG. 7. The stirringstick 167 has on its surface a spiral vane 167 a and thus has a spiralshape. The stirring stick 167 extends, for example, between both endportions of the mixing chamber 164, and one end portion thereof isconnected to a rotation driving section 168 attached to, for example, aside face of the main body 143 a. The rotation driving section 168 has apower generator such as, for example, a motor to be capable of rotatingthe stirring stick 167 around the axis. Therefore, when the developingsolution and the pure water flow into the mixing chamber 164, thestirring stick 167 can be rotated to stir the developing solution andthe pure water.

A plurality of discharge ports 169 opening in a lower surface of themain body 143 a communicate with a lower portion of the mixing chamber164. The discharge ports 169 are arranged in a line along thelongitudinal direction of the main body 143 a at equal intervals betweenboth end portions of the main body 143 a. As shown in FIG. 6, each ofthe discharge ports 169 is smaller in diameter than the mixing chamber164, and each flow path thereof narrows down when the fluid flows fromthe mixing chamber 164 to the discharge ports 169.

According to the developing solution supply nozzle 143 as structuredabove, it is possible to mix the developing solution introduced into thedeveloping solution storage chamber 160 and the pure water introducedinto the liquid storage chamber 161 at a predetermined ratio in themixing chamber 164 and stir the developing solution and the pure water,so that a developing solution with a predetermined concentration and ata predetermined temperature can be produced and the produced developingsolution can be discharged uniformly from the discharge ports 169.

Incidentally, the aforesaid other second arm 142 attached to the rail140 supports a rinsing liquid supply nozzle 180 as shown in FIG. 5. Thesecond arm 142 is movable in the Y direction on the rail 140 when drivenby, for example, a driving mechanism 181. Further, the second arm 142 isalso movable in the up/down direction when driven by the drivingmechanism 181. The second arm 142 is capable of moving the rinsingliquid supply nozzle 180 from a standby section 182 provided outside thecup 122 on the Y-direction positive side to a position above the centerportion of the wafer W in the cup 122. The rinsing liquid supply nozzle180 communicates with a not-shown rinsing liquid supply source providedoutside the developing unit 30 and is capable of discharging in adownward direction the rinsing liquid supplied from the rinsing liquidsupply source.

Next, the photolithography process of the wafer W conducted in thecoating and developing system 1 as structured above will be described.First, when the cassette C housing a plurality of unprocessed wafers Wis placed on the mounting table 5, one of the wafers W is taken out ofthe cassette C and is carried by the wafer carrier 7 to the temperaturecontroller 50 in the third processing unit group G3. The wafer W carriedto the temperature controller 50 is temperature-adjusted to apredetermined temperature and is carried to the bottom coating unit 23by the first carrier 10 thereafter. The wafer W carried to the bottomcoating unit 23 is coated with a liquid material of an anti-reflectivefilm, and an anti-reflective film B is formed on the surface of thewafer W as shown in (a) in FIG. 8. A liquid material soluble in thedeveloping solution used for the development treatment in a laterprocess is used to form the anti-reflective film B.

The wafer W on which the anti-reflective film B is formed is carried bythe first carrier 10 to the heating unit 82, the high-temperaturethermal processing unit 55, and the high-precision temperaturecontroller 60 in sequence and is subjected to predetermined processingin each of the units. Thereafter, the wafer W is carried to the resistcoating unit 20, where a resist film R is formed on the anti-reflectivefilm B ((b) in FIG. 8).

The wafer W on which the resist film R is formed is carried to thepre-baking unit 61 by the first carrier 10 and then is carried by thesecond carrier 11 to the edge exposure unit 84 and the high-precisiontemperature controller 73 in sequence to be subjected to predeterminedprocessing in each of the units. Thereafter, the wafer W is carried bythe wafer carrier 102 of the first interface part 100 to the buffercassette 104. Next, the wafer W is carried by the wafer carrier 106 ofthe second interface part 101 to the not-shown aligner. The not-shownaligner exposes the wafer W in a predetermined pattern ((c) in FIG. 8).The hatched portions of the resist film R in (c) in FIG. 8 are portionsthat have been exposed. The wafer W having been subjected to theexposure processing is carried by the wafer carrier 106 and the wafercarrier 102 to the buffer cassette 103 via the buffer cassette 104.Thereafter, the wafer W is carried by the wafer carrier 102 to, forexample, the post-exposure baking unit 74, and after being subjected tothe heating processing, is carried by the second carrier 11 to thehigh-precision temperature controller 71. Thereafter, the wafer W iscarried to the developing unit 30.

Here, the development treatment conducted in the developing unit 30 willbe detailed. When the wafer W is carried into the developing unit 30 bythe second carrier 11, the wafer W is suction-held on the spin chuck 120as shown in FIG. 4. Subsequently, as shown in FIG. 5, the developingsolution supply nozzle 143 having been on standby in the standby section145 moves in the Y direction toward the positive side to reach a startposition P1 which is short of the end of the wafer W on the Y-directionnegative side in a plane view. Thereafter, the developing solutionsupply nozzle 143 moves down to come close to the height of the surfaceof the wafer W.

Thereafter, the valve 156 and the valve 157 are opened, so that thedeveloping solution with the predetermined concentration in thedeveloping solution supply source 151 and the pure water in the liquidsupply source 154 are supplied to the developing solution supply nozzle143 at predetermined flow rates respectively. Incidentally, thedeveloping solution in the developing solution supply source 151 and thepure water in the liquid supply source 154 may be adjusted to the sametemperature in advance by the temperature control sections 152, 155.Further, the flow rates of the developing solution and the pure watersupplied to the developing solution supply nozzle 143 are set so thatthe developing solution, which is produced by mixing the developingsolution and the pure water in the developing solution supply nozzle143, has a desired concentration. The developing solution supplied tothe developing solution supply nozzle 143 is tentatively stored in thedeveloping solution storage chamber 160 to flow into the mixing chamber164 through the first communicating paths 165. The pure water suppliedto the developing solution supply nozzle 143 is tentatively stored inthe liquid storage chamber 161 to flow into the mixing chamber 164through the second communicating paths 166. In the mixing chamber 164 towhich the developing solution and the pure water has flowed, thestirring stick 167 is rotated by the rotation driving section 168 tostir and mix the developing solution and the pure water in the mixingchamber 164, so that a developing solution H1 at a predeterminedconcentration is produced in the mixing chamber 164. Note that theconcentration optimum for the development of the resist film R isselected as the concentration of the developing solution H1.

The developing solution H1 produced in the mixing chamber 164, afterresiding in the mixing chamber 164 and being fully stirred, flows intothe discharge ports 169 formed in the bottom part thereof to beuniformly discharged from the discharge ports 169. Thus, the developingsolution supply nozzle 143 discharges the developing solution H1 to asubstantially belt-shaped area between both end portions.

When the discharge of the developing solution H1 is started at the startposition P1, the developing solution supply nozzle 143 moves in the Ydirection from the start position P1 to a stop position P2 which islocated outside the end portion of the wafer W on the Y-directionpositive side shown in FIG. 5. While the developing solution supplynozzle 143 thus moves, the developing solution H1 is supplied to thewafer W, so that a solution film of the developing solution H1 is formedon the wafer W ((d) in FIG. 8). On the wafer W on which the solutionfilm of the developing solution H1 is formed, the exposed portions ofthe resist film R are dissolved in the developing solution H1, and theresist film R is developed. When the developing solution supply nozzle143 moves to the stop position P2, for example, the valves 156, 157 areclosed to stop the discharge of the developing solution H1 from thedeveloping solution supply nozzle 143. The developing solution supplynozzle 143 which has stopped supplying the developing solution H1 isreturned to, for example, the start position P1 where the discharge ofthe developing solution was started.

When a predetermined period of time passes after the developing solutionsupply nozzle 143 is returned to the start position P1, the valves 156,157 are opened again, so that the developing solution and the pure waterare supplied to the developing solution supply nozzle 143. The flowrates of the developing solution and the pure water at this time areadjusted so that a developing solution H2 lower in concentration thanthe developing solution H1 is produced in the developing solution supplynozzle 143. The concentration of the developing solution H2 is adjustedto, for example, a concentration with which the developing solution H2is very low in property of dissolving the resist film R and dissolvesonly the anti-reflective film B, for example, a concentration half theconcentration of the developing solution H1 or lower, for example, aconcentration that is about 20% to 50% of the concentration of thedeveloping solution H1. Note that when the concentration of thedeveloping solution H1 is about 0.26 mol/l, the concentration of thedeveloping solution H2 is preferably adjusted to about 0.06 mol/l toabout 0.11 mol/l.

The developing solution supply nozzle 143 is kept on standby whiledischarging the developing solution H2 at the start position P1. Then,the developing solution supply nozzle 143 moves in the Y directiontoward the positive side when the dissolution of the exposed portions ofthe resist film R reaches, as shown in (a) in FIG. 9, the surface of theanti-reflective film B on the wafer W having the developing solution H1thereon. The developing solution supply nozzle 143 moves from the startposition P1 to the stop position P2 as it does when supplying thedeveloping solution H1. The developing solution H1 on the wafer W isreplaced by the developing solution H2, so that a solution film of thedeveloping solution H2 is formed on the wafer W ((b) in FIG. 9). Theanti-reflective film B in the exposed portions is dissolved by thedeveloping solution H2 to be removed ((c) in FIG. 9).

The developing solution supply nozzle 143 which has stopped at the stopposition P2 stops discharging the developing solution H2 and is returnedto the standby section 145. When the developing solution supply nozzle143 is returned to the standby section 145, the rinsing liquid supplynozzle 180 that has been on standby in, for example, the standby section182 moves to a position above the center portion of the wafer W, and forexample, the inner cup 123 moves up to surround the periphery of thewafer W. Thereafter, the wafer W is rotated by the spin chuck 120 andthe rinsing liquid supply nozzle 180 supplies the rinsing liquid to thecenter portion of the wafer W. Consequently, the developing solution H2on the wafer W is rinsed away by the rinsing liquid. When the rinsingliquid is supplied for a predetermined period of time and the washing ofthe wafer W is finished, the supply of the rinsing liquid is stopped,and the rinsing liquid is thereafter scattered for drying by thehigh-speed rotation of the wafer W.

Thereafter, the rotation of the wafer W is stopped and the wafer W isdelivered to the second carrier 11 from the spin chuck 120 to be carriedout of the developing unit 30. Thus, a series of the developmenttreatment of the wafer W is finished.

The wafer W having been subjected to the development treatment iscarried to, for example, the post-baking unit 65, is carried by thefirst carrier 11 to the transition unit 51, and thereafter is returnedto the cassette C by the wafer carrier 7. Thus, a series of thephotolithography processes in the coating and developing system 1 isfinished.

According to the embodiment described above, in the developmenttreatment, after the developing solution H1 is supplied to the wafer Wto develop the resist film R, the developing solution H2 lower inconcentration than the developing solution H1 is supplied to the wafer Wto dissolve the anti-reflective film B. Therefore, unlike in the priorart, it is not necessary to use plasma for etching the anti-reflectivefilm for removal, so that the anti-reflective film B can be removedwithout affecting the resist film R. Further, the new developingsolution H2 for dissolving the anti-reflective film B is supplied to thewafer W after the development of the resist film R is finished.Therefore, when the dissolution of the anti-reflective film B isstarted, the surface of the wafer W is under the uniform condition, sothat the anti-reflective film B can be removed uniformly on the surfaceof the wafer W.

Further, the developing solution H2 dissolving the anti-reflective filmB is lower in property of dissolving the resist film than the developingsolution H1. Therefore, the resist film R is prevented from dissolvingwhen the anti-reflective film B is dissolved. Moreover, the developingsolution supply nozzle 143 has the discharge ports 169 that are arrangedin an area longer than the dimension of the wafer W, and the developingsolution supply nozzle 143 discharges the developing solution H2 whilemoving above the wafer W, thereby forming the solution film of thedeveloping solution H2 on the anti-reflective film B. Therefore, it ispossible to perform the supply of the developing solution H2 to thewhole surface of the wafer W properly and in a short time.

Since the mixing chamber 164 mixing the developing solution in thedeveloping solution storage chamber 160 and the pure water in the liquidstorage chamber 161 is provided in the developing solution supply nozzle143, it is possible to adjust and change the concentration of thedeveloping solution to be discharged from the discharge ports 169 asrequired. As a result, the developing solution H1 is discharged fordeveloping the resist film R and the developing solution H2 isdischarged for dissolving the anti-reflective film B, so that theaforesaid development treatment can be suitably carried out. Further,since the stirring stick 167 is provided in the mixing chamber 164 andthe stirring stick 167 can be actively rotated by the rotation drivingsection 168, it is possible to fully stir and mix the developingsolution and the pure water flowing into the mixing chamber 164 toproduce the developing solutions H1, H2 without any concentrationvariation. As a result, the developing solution without anyconcentration variation is supplied to the wafer W, so that the resistfilm R and the anti-reflective film B can be uniformly dissolved on thesurface of the wafer W. Moreover, the stirring stick 167 has a spiralshape, which can further improve the stirring effect thereof.

Incidentally, the stirring stick 167 described in the above embodimentis formed in a spiral shape by a spiral vane 167 a attached to thesurface thereof, but it may be formed in the spiral shape by forming aspiral groove 200 a on a surface of the stirring stick 200 as shown inFIG. 10. Further, a stirring stick 210 may be formed of a porousmaterial as shown in FIG. 11. In such a case, the developing solutionand the pure water permeate through the porous material and thedeveloping solution and the pure water are mixed in the course of thepermeation, which can provide a sufficient stirring effect. At thistime, a spiral vane may be attached to the stirring stick 210.

In the embodiment described above, the diameter of each of the dischargeports 169 of the developing solution supply nozzle 143 is constant, butthe diameter of each of discharge ports 220 may become gradually largertoward the lower surface of the main body 143 a from the mixing chamber164 as shown in FIG. 12. In such a case, the flow path extending fromthe mixing chamber 164 to the discharge port 220 narrows down once onthe lower surface of the mixing chamber 164 and gradually widens towardthe opening of the discharge port 220 thereafter. Such a structure canpromote the mixture of the developing solution and the pure water sincethe sufficient residence time of the developing solution in the mixingchamber 164 can be secured. Further, it is possible to reduce thedischarge pressure of the discharged developing solution in thedischarge ports 220, and as a result, the collision of the developingsolution with the wafer W is buffered, so that a development flaw causedby the collision can be reduced.

As shown in FIG. 13, the first communicating paths 165 connecting thedeveloping solution storage chamber 160 and the mixing chamber 164, andthe second communicating paths 166 connecting the liquid storage chamber161 and the mixing chamber 164, which are descried in the embodimentabove, may be formed such that the flow directions of the developingsolution and the pure water are deviated from the axial center of astirring stick 230, and the developing solution and the pure waterflowing in the mixing chamber 164 collide with the surface of thestirring stick 230. In this case, the stirring stick 230 may be disposedin the mixing chamber 164 to be freely rotatable without having therotation driving section. In such a case, the developing solution andthe pure water flowing in the mixing chamber 164 rotate the stirringstick 230, which enables full stirring in the mixing chamber 164.

In the development treatment process described in the above embodiment,the developing solution H2 is supplied to dissolve the anti-reflectivefilm B immediately after the developing solution H1 is supplied todevelop the resist film R. However, the developing solution H2 may besupplied after the wafer W is once rotated by the spin chuck 120 toscatter the developing solution H1, following the completion of thedevelopment of the resist film R. This can prevent excessive developmentof the resist film R by the developing solution H1.

In the embodiment described above, the developing solution H2 lower inconcentration than the developing solution H1 is supplied to the wafer Wfor dissolving the anti-reflective film B. However, the developingsolution H2 lower in temperature than the developing solution H1 may besupplied for dissolving the anti-reflective film B. In this case, forexample, a developing solution instead of the pure water is stored inthe liquid supply source 154, and the developing solutions in thedeveloping solution supply source 151 and the liquid supply source 154are set to different temperatures from each other by the temperaturecontrol sections 152, 155. Then, when the resist film R is developed,the developing solutions different in temperature are supplied to thedeveloping solution supply nozzle 143 from the developing solutionsupply source 151 and the liquid supply source 154. In the mixingchamber 164 in the developing solution supply nozzle 143, the developingsolutions different in temperature are mixed at a predetermined ratio toproduce the developing solution H1 at a predetermined temperature, andthe developing solution H1 is supplied to the wafer W. When theanti-reflective film B is to be dissolved, the ratio of the flow ratesof the respective developing solutions supplied from the developingsolution supply source 151 and the liquid supply source 154 is changed.Consequently, the mixing ratio of the developing solutions mixed in thedeveloping solution supply nozzle 143 is changed, the developingsolution H2 lower in temperature than the developing solution H1 isproduced, and the developing solution H2 is supplied to the wafer W. Insuch a case, it is also possible to appropriately dissolve only theanti-reflective film B since the developing solution H2 lower inproperty of dissolving the resist film R is supplied to the wafer whenthe anti-reflective film B is dissolved.

Incidentally, in the embodiment described above, the developing solutionH2 supplied for dissolving the anti-reflective film B is lower inconcentration or temperature than the developing solution H1 suppliedfor developing the resist film R. However, the developing solution H2may be lower both in concentration and in temperature.

The embodiment descried above only shows an example of the presentinvention, and the present invention is not limited to this embodimentbut can take various forms. For example, the base film of the resistfilm R in the embodiment described above is the anti-reflective film B,but it may be other base film such as, for example, a resist film of adifferent kind. Further, the liquid supplied to the wafer W fordissolving the anti-reflective film B is the developing solution H2, butit may be other developing solution dissolving only the anti-reflectivefilm B. Moreover, in the embodiment described above, the wafer W is usedas a substrate, but the present invention is applicable to a substrateother than a wafer, for example, other substrates such as FPD (flatpanel display) substrate, a mask substrate, and a reticle substrate.

The present invention is useful in removing a base film of a resist filmin a photolithography process of substrate processing.

1. A developing method comprising the steps of: forming ananti-reflective film on a resist film, portions of said resist filmbeing in a pattern, and thereafter; depositing a produced developingsolution onto said resist film, said produced developing solutiondissolving said portions of the resist film, and thereafter; depositingan adjusted developing solution onto said anti-reflective film and ontoremaining portions of the resist film, said adjusted developing solutiondissolving said anti-reflective film faster than dissolving saidremaining portions of the resist film, wherein at least one property ofa developing solution is lower within said adjusted developing solutionthan within said produced developing solution, said at least oneproperty being from the group consisting of a concentration and atemperature.
 2. A developing method as set forth in claim 1, whereinsaid adjusted developing solution dissolves said anti-reflective filmwithout dissolving said remaining portions of the resist film.
 3. Adeveloping method as set forth in claim 1, wherein said anti-reflectivefilm inhibits a reflection of light.
 4. A developing method as set forthin claim 1, wherein said anti-reflective film is between a wafer andsaid resist film.
 5. A developing method as set forth in claim 1,wherein a liquid material is soluble in said developing solution, saidliquid material becoming said anti-reflective film.
 6. A developingmethod as set forth in claim 1, wherein said developing solution iswithin said produced developing solution and said adjusted developingsolution.
 7. A developing method as set forth in claim 1, wherein aconcentration of a liquid is higher in said adjusted developing solutionthan within said produced developing solution.
 8. A developing method asset forth in claim 7, wherein said liquid is within said produceddeveloping solution and said adjusted developing solution.
 9. Adeveloping method as set forth in claim 7, wherein said liquid is water.10. A developing method as set forth in claim 7, wherein said produceddeveloping solution is mixed with said liquid, a stirring stick within anozzle mixing said produced developing solution with said liquid.
 11. Adeveloping method as set forth in claim 10, wherein said adjusteddeveloping solution is mixed with said liquid, said stirring stickwithin the nozzle mixing said adjusted developing solution with saidliquid.
 12. A developing method as set forth in claim 10, wherein saidproduced developing solution and said adjusted developing solution aredischarged from said nozzle.
 13. A developing method as set forth inclaim 1, wherein said remaining portions of the resist film mask saidanti-reflective film.
 14. A developing method as set forth in claim 1,wherein said at least one property is said concentration.
 15. Adeveloping method as set forth in claim 1, wherein said at least oneproperty is said temperature.
 16. A developing method as set forth inclaim 1, wherein said at least one property is said concentration andsaid temperature.